Taming technique??

[mangoandmimi]

The only time I've used those tweezers is when feeding a live mealworm. It would probably be more beneficial to offer food between your fingers really, at least the larger bits. Scatter feeding slowly, with your hand in the cage where they can see & sense you, is easier and they do learn that you're the one who's feeding them.
Are you sure the bites are food related or could it be from something like being territorial in the cage? Hamsters generally don't bite fingers because they think it's food really, they'll usually only bite with reason.
Biting is something you just have to work through unfortunately, if you're nervous of getting bitten you could try gloves although they're a bit of a last resort as lots of times they don't help with taming all that much.